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91.
Journal of Plant Diseases and Protection - The effect of salicylic acid (SA) is hypothesized to be a natural signal that triggers the systemic induction of phenolics, pathogenesis-related proteins...  相似文献   
92.
Vanilla, Vanilla planifolia Andrews, is native to Mexico and Central America, but is now cultivated in other parts of the tropics. Continuous clonal propagation has resulted in very little variability for crop improvement programmes in vanilla. In this study, an attempt has been made to increase the spectrum of variation by interspecific hybridization with Vanilla aphylla, an Indian species which is tolerant to Fusarium. Interspecific hybrids were successfully produced and morphological characters and molecular profiles revealed the true hybridity of the progenies. Ten seedling progenies of V. planifolia, and four interspecific hybrids obtained from crosses between V. planifolia (female) and V. aphylla (male) using a number of different loci as markers were evaluated and 319 amplified fragment length polymorphisms (AFLPs) and 83 random amplified polymorphic DNAs (RAPDs) loci were marked. The profiles indicate similarity between the parents, selfed progenies and interspecific hybrids and that all the progenies tested were variable when compared to each other, which can be exploited for crop improvement in vanilla. This is the first report in vanilla, indicating that RAPD and AFLP profiles coupled with morphological characters can be utilized to assess the variability and hybrid nature of genotypes and of successful interspecific hybridization and production of hybrids between V. planifolia and V. aphylla.  相似文献   
93.
Introduction of two systems of agroforestry to the farmers portfolio is evaluated for their changes in cropping pattern, input use, income generation, farmers attitude towards risk and nutrient availability. Two different types of farmers are studied under both irrigated and dryland farming systems. Farm survey data collected from south Indian villages have been used with a mean-variance framework to identify the risk aversion levels of farmers. The results indicate that the risk-taking preferences of farmers should be given consideration in evaluating the impact of agroforestry systems. Among the two agroforestry systems analyzed, the one with drumstick is shown to increase the risk of crop production while the one with leucaena reduces the risk and enables farmers to invest in more risky cash crops. The impact of agroforestry on crop allocation, input use and income differs due to the differences in resource availability of farmers. The influence of agroforestry on nutrient availability of the farm households also differs based on the components of agroforestry, orientation of farming and the nature of farming systems. It is argued that design of agroforestry systems should consider differences in resource constraints in farming systems and risk attitudes of farmers towards their allocation decisions and that such considerations would largely enhance the successful adoption of agroforestry in developing countries.  相似文献   
94.
One new glycoside derivative from syringic acid and one new phenol glycoside, curculigoside E (1) and orchioside D (2), were isolated and characterized from the rootstock of Curculigo orchioides collected in the Nawalparasi District (Nepal). The structures of the new isolated compounds were elucidated by means of spectroscopic methods such as 1D, 2D NMR and MS.  相似文献   
95.
Two new cell lines, designated RE and CB, were derived from the eye of rohu, Labeo rohita , and the brain of catla, Catla catla , respectively. The cell lines were maintained in Leibovitz's L-15 supplemented with 20% foetal bovine serum. The RE cell line was sub-cultured for more than 70 passages and the CB cell line for more than 35 passages. The RE cells are rounded and consist predominantly of epithelial cells. The CB cell line consists of predominantly fibroblastic-like cells. Both cell lines are able to grow at temperatures between 25 and 32 °C with an optimum of 28 °C. The growth rate of the cells increased as the foetal bovine serum concentration increased from 2% to 20% at 28 °C, with optimum growth at concentrations of 15% or 20% foetal bovine serum. The cells were successfully cryopreserved and revived at different passage levels. The cell lines were not susceptible to four marine fish viruses. Extracellular products from Aeromonas sp . were toxic to the cell lines. When the cells were transfected with plasmid eukaryotic green fluorescent protein (pEGFP [Clontech, Carlsbad, CA, USA]) vector DNA, a significant fluorescent signal was observed suggesting that these cell lines could be a useful tool for transgenic and genetic manipulation studies. Polymerase chain reaction amplification of mitochondrial 12S rRNA from rohu and catla confirmed that the cell lines originated from these fish species. The cell lines were further characterized by immunocytochemistry using confocal laser scanning microscopy.  相似文献   
96.
罗氏沼虾几丁质酶3B基因的克隆及其在蜕皮周期中的表达   总被引:1,自引:1,他引:0  
罗氏沼虾的生长发育及繁殖都与蜕皮紧密相关。几丁质酶是甲壳动物在蜕皮过程中最重要的酶之一。本研究对罗氏沼虾蜕皮周期外观特征和腹肢刚毛进行了观察描述,克隆并分析了罗氏沼虾的几丁质酶Ⅲ基因(MrChi3B),制备了几丁质酶Ⅲ蛋白的多克隆抗体,研究了其在蜕皮周期中的表达。罗氏沼虾几丁质酶基因cDNA的开放阅读框为1 143 bp,编码380个氨基酸,大小为41.91 ku。通过氨基酸序列比对发现,MrChi3B与日本沼虾几丁质酶基因(Chi3B)的同源性最高,为94%。MrChi3B含有一个糖苷键水解酶家族18的催化域。实时定量PCR (qRT-PCR)和蛋白印迹法(WB)检测结果显示,MrChi3B在罗氏沼虾多个组织中均有表达,但是不同组织中的表达有差异。在蜕皮期之后,其在胃、表皮和肌肉中的表达量显著上升。在胃中其表达量在蜕皮间期达到最高;在表皮和肌肉中其表达量在蜕皮后期达到最高;肠中的表达量在蜕皮前期和蜕皮期有所上升;眼柄期的表达量在所有蜕皮期都偏低。本研究结果为进一步研究几丁质酶的功能提供参考依据。  相似文献   
97.
TMV 2 is a very popular peanut variety among the Indian farmers, but it is highly susceptible to fungal foliar diseases like late leaf spot (LLS) and rust. Marker‐assisted backcrossing (MABC) in TMV 2 using foliar disease‐resistant donor, GPBD 4 and the disease resistance‐linked markers (GM2009, GM2079, GM2301, GM1839 and IPAHM103) resulted in a large number of backcross populations and also straight cross populations. Foreground selection followed by field evaluation under disease epiphytotic conditions could identify a few superior genotypes. Two homozygous backcross lines TMG‐29 and TMG‐46 showed enhanced resistance to LLS and rust diseases (score of 3.00 for both) along with 71.0% and 62.7% increase in the pod yield per plot, respectively, over the check, TMV 2. These foliar disease‐resistant and productive lines can be released as commercial varieties or can be used as genetic resources in the peanut improvement.  相似文献   
98.
Stenohaline freshwater fish with narrow salinity tolerance are susceptible to saline stress from global climate change and anthropogenic activities. The present study elucidated that saline exposure during the sensitive window of preparatory phase of oocyte maturation significantly affected gonadosomatic index, ovarian histology and morphometric features of oocytes in a stenohaline freshwater catfish, Heteropneustes fossilis (Bloch, 1794) in a dose (2 ppt, 5 ppt)—and duration (8, 24 days)‐dependent manner. The gonads of H. fossilis show annual maturation cycle. Loss of integrity of ovigerous lamellae, disruption of ovarian stroma, disrupted oolemma, ooplasmic vacuolization, damaged germinal vesicles and altered morphometry of previtellogenic oocytes, such as chromatin‐nucleolus, early perinucleolar and late perinucleolar, elucidated consistent effects of saline exposure except at 8 days exposure to 2 ppt of saline. Increased salinity might have affected the transmembrane ion/water transport and disrupted the osmotic balance in ovary that eventually led to impairment in growth of ovary and oocyte maturation. The susceptibility of ovary to comparatively less concentrations of saline exposure might be due to sensitiveness of ovary/oocytes during the early phase of growth. Fluctuating salinity along with other stressors can affect metabolic and growth rates, fecundity and ultimately survival of fish.  相似文献   
99.
The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 103 to 3.76 × 105 cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 105 cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
100.
The vapor-phase toxicity of Derris scandens Benth.-derived constituents was evaluated against four stored-product pests ( Callosobruchus chinensis L., Sitophilus oryzae L., Rhyzopertha dominica L., and Tribolium castaneum H.) using fumigation bioassays and compared to those of commonly used insecticides. The structures of all constituents of were characterized by spectroscopic analyses [nuclear magnetic resonance (NMR) and mass spectrometry]. The sensitivity of the test insect to compounds varied with exposure time, concentration, and insect species. Over 100% mortality after 24 h was achieved with the compounds osajin (2), scandinone (5), sphaerobioside (8), and genistein (9) against all of the test insects, while laxifolin (3) and lupalbigenin (4) showed 100% mortality after 72 h against T. csataneum and R. dominica . Scandenone (1), scandenin A (6), and scandenin (7) were less effective. Among the insects, C. chinensis , S. oryzae , and R. dominica were more susceptible to the treatments, whereas T. castaneum was less susceptible. The results of fumigation tests indicated that compounds from D. scandens whole plant extract are potential candidates to control stored-product pests.  相似文献   
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